全文获取类型
收费全文 | 614篇 |
免费 | 35篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 221篇 |
金属工艺 | 17篇 |
机械仪表 | 13篇 |
建筑科学 | 27篇 |
能源动力 | 25篇 |
轻工业 | 114篇 |
水利工程 | 3篇 |
武器工业 | 1篇 |
无线电 | 28篇 |
一般工业技术 | 91篇 |
冶金工业 | 7篇 |
原子能技术 | 1篇 |
自动化技术 | 95篇 |
出版年
2023年 | 2篇 |
2022年 | 20篇 |
2021年 | 36篇 |
2020年 | 8篇 |
2019年 | 13篇 |
2018年 | 22篇 |
2017年 | 23篇 |
2016年 | 24篇 |
2015年 | 17篇 |
2014年 | 29篇 |
2013年 | 66篇 |
2012年 | 39篇 |
2011年 | 26篇 |
2010年 | 31篇 |
2009年 | 27篇 |
2008年 | 20篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 28篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 8篇 |
1973年 | 4篇 |
1960年 | 1篇 |
排序方式: 共有650条查询结果,搜索用时 15 毫秒
41.
42.
When V. V. Nalimov in his important book Naukometriya (Moskva 1969) postulated research on the process of developement of science with the aid of quantitative methods, he listed
many different indicators. There were among them the number and growth of scientific publications — books and periodicals,
the number of scientists, the level of expenditure.
This article shows that the importance of these indicators was recognised by earlier authors.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
43.
Ryszard Rywotycki 《Food chemistry》2007,101(2):540-548
The studies aimed to determine the occurrence and formation of nitrosamine contamination levels with dimethylnitrosamine (DMNA) and diethylnitrosamine (DENA) in meat of various kinds, species and genders of farm animals slaughtered at meat processing plants all over Poland. The meat after cooling, cutting and jointing was classified, then comminuted and divided into several experimental variants. Moreover, the effect of the most frequent functional additives used in food industry, such as sodium chloride and sodium ascorbate, and baking process upon the level of the meat pollution was researched. Nitrosamine (DMNA and DENA) concentrations were assessed by Varian 3400 gas chromatograph coupled with Finnigan MAT ITD 800 spectrometer. The quantitative and qualitative states of respective nitrosamines were determined by comparing the chromatogram values. 相似文献
44.
45.
Jrmy Lamarche Luisa Ronga Joanna Szpunar Ryszard Lobinski 《International journal of molecular sciences》2021,22(12)
Selenoprotein P (SELENOP) is an emerging marker of the nutritional status of selenium and of various diseases, however, its chemical characteristics still need to be investigated and methods for its accurate quantitation improved. SELENOP is unique among selenoproteins, as it contains multiple genetically encoded SeCys residues, whereas all the other characterized selenoproteins contain just one. SELENOP occurs in the form of multiple isoforms, truncated species and post-translationally modified variants which are relatively poorly characterized. The accurate quantification of SELENOP is contingent on the availability of specific primary standards and reference methods. Before recombinant SELENOP becomes available to be used as a primary standard, careful investigation of the characteristics of the SELENOP measured by electrospray MS and strict control of the recoveries at the various steps of the analytical procedures are strongly recommended. This review critically discusses the state-of-the-art of analytical approaches to the characterization and quantification of SELENOP. While immunoassays remain the standard for the determination of human and animal health status, because of their speed and simplicity, mass spectrometry techniques offer many attractive and complementary features that are highlighted and critically evaluated. 相似文献
46.
47.
Malgorzata Nogala-Kalucka Magdalena Rudzinska Ryszard Zadernowski Aleksander Siger Inga Krzyzostaniak 《Journal of the American Oil Chemists' Society》2010,87(12):1481-1487
The lipophilic and hydrophilic antioxidants were evaluated in eight plants: safflower (Carthamus tinctorius), viper’s bugloss (Echium vulgare), quince (Cydonia vulgaris), evening primrose (Oenothera biennis), rose mosqueta (Rosa affinis rubiginosa), black seed (Nigella sativa), sea buckthorn (Hippophae rhamnoides) and borage (Borago officinales). The highest amounts of tocopherols were contained in seeds of borage and sea buckthorn (66.9 mg/100 g and 45.9 mg/100 g,
respectively). The sea buckthorn seed lipids had the highest amount of total sterols (10.4 mg/g of lipids). The predominant
form was campesterol. Sitosterol was the major sterol in the lipids of other tested seeds. The content of phenolic compounds
ranged from 736.5 mg/100 g dry matter (d.m.) (evening primrose) to 74.8 mg/100 g d.m. (safflower). The highest antioxidant
activity, expressed in % scavenged DPPH· free radicals, was observed for evening primrose (91.2%), while the lowest for safflower
(36.2%). The correlation coefficient between the level of phenolic compounds and antioxidant activity was 0.53. 相似文献
48.
Crude catechins extract from Chinese green tea were fractionated using Sephadex LH‐20 column chromatography. The fraction containing (–)‐epigallocatechin‐3‐gallate (EGCG) was then subjected to a semipreparative high‐performance liquid chromatography (HPLC). Using a mobile phase of water : dimethyl formamide : methanol : acetic acid (157 : 49 : 2 : 1 v/v/v/v( the mixture of two methylated catechins was separated and isolated. According to mass spectrometry (MS) and nuclear magnetic resonance (1H‐NMR) date, these compounds were identified as (–)‐epigallocatechin‐3‐(3‐O‐methylgallate) and (–)‐epigallocatechin‐3‐(4‐O‐methylgallate). 相似文献
49.
Krzysztof Marycz Monika Marędziak Jakub Grzesiak Ryszard Fryczkowski Jadwiga Laska 《Polymer-Plastics Technology and Engineering》2016,55(18):1897-1907
Articular cartilage dysfunctions are major cause of pain and disability and lead to serious health complications. Cell-based therapies are proposed as treatment methods for cartilage regeneration. In this study, we proposed polyurethane/poly(L-lactide-co-D, L-lactide)-based electrospun nonwovens as carriers for the delivery of human adipose-derived stromal stem cells. We found that 6:4 and 8:2 polyurethane/poly(L-lactide-co-D, L-lactide) initially enhance proliferative rate of human adipose-derived stromal stem cells, shorten their population doubling time, promote creation of functional chondrogenic nodules during chondrogenic differentiation, improve the collagen-2-to-collagen-1 protein ratio, and upregulate the expression of collagen-2 and aggrecan genes. 相似文献
50.
We consider relational structures such that is a set and are two binary relations on . For a number of different classes of structures we show that any structure can be represented as the intersection of its
maximal extensions. Such a property – called extension completeness – can be seen as a generalisation of Szpilrajn's theorem
which states that each partial order is the intersection of its total order extensions. When can be interpreted as causality and as ‘weak’ causality we obtain a model of concurrent histories generalising that based on causal partial orders.
Received 1 February 1994 / 6 May 1996 相似文献